1. Field of the Invention
The present invention relates to power shift transmissions, and in particular to large heavy duty transmissions for use in work vehicles.
2. Description of the Related Art
Heavy duty work vehicles, such as tractors, industrial equipment, combines and the like, generally require transmissions that have a wide range of available speeds. It is quite common with these vehicles to set the throttle to run the engine at a fixed number of revolutions per minute, with ground speed then being adjusted by changing the gear ratios in the transmission, rather than changing the amount of fuel provided to the engine.
Providing such a large number of gear ratios typically results in a physically large transmission with a correspondingly large number of parts. However, to reduce the cost of the transmission, it is desirable to reduce the size of the transmission as much as possible, thereby reducing the amount of materials used. Similarly, it is desirable to reduce the number of different parts as far as possible, thereby reducing the manufacturing costs.